[Audio & Video] xmartO 8 Channel 960p HD Wireless Surveillance Camera System with 8 HD Infrared Outdoor WiFi Cameras and 2TB Hard Drive, Dream Liner WiFi Relay, NVR Built-in Router, Auto-Pair With audio support, the xmartO camera system lets you add microphone to each camera; letting you see, hear and record AV (audio & video). xmartO Dream Liner WiFi relay tech., boost WiFi distance 2 to 3 times. Dream Liner technology uses cameras in middle as repeaters, which doubles/ triples the current WiFi distance. Kit features incredible AUTO-PAIR technology; making sure you only need to plug them in power to start working. Plug N Play for real. Easy live view & remote playback on your smartphone and computer from anywhere anytime; receive email alerts and mobile notifications when motion is detected. 2TB hard drive is pre-installed, allows for 24/7 continuous recording up to 40 days, record even longer with motion detection recording